The present invention relates to a method for producing composite material, and, more particularly, relates to method for producing composite material composed of a reinforcing material such as fiber, wire, powder, short staple fiber, or the like embedded within a matrix of metal.
There are known various types of reinforced materials, in which powder, short staple fibers, or fibers of a reinforcing material such as metal, alumina, boron, carbon, or the like are embedded within a matrix of metal such as aluminum or magnesium or the like to form a composite material, and various methods of production for such composite or reinforced material have already been proposed.
One such known method for producing such fiber reinforced material is called the diffusion adhesion method, or the hot press method. In this method, a number of sheets are made of fiber and matrix metal by spraying molten matrix metal onto sheets or mats of fiber in a vacuum; and then these sheets are overlaid together, again in a vacuum, and are pressed together at high temperature so that they stick together by the matrix metal diffusing between them. This method has the disadvantage of requiring complicated manipulations to be undertaken in the inside of a vacuum device of a large size. This is clumsy, difficult, and expensive, and accordingly this diffusion adhesion method is unsuitable for mass production, due to high production cost and production time involved therein.
Another known method for producing such fiber reinforced material is called the infiltration soaking method, or the autoclave method. In this method, fiber is filled into a container, the fiber filled container is then evacuated of atmosphere, and then molten matrix metal is admitted into the container under pressure, so that this molten matrix metal infiltrates into the fiber within the container. This method, also, requires the use of a vacuum device for producing a vacuum, in order to provide good contact between the matrix metal and the reinforcing material at their interface, without interference caused by atmospheric air trapped in the interstices of the fiber mass. Further, this autoclave method also has the additional disadvantage that, if the molten matrix metal is magnesium, it is difficult to attain the required proper high degree of vacuum, due to the high vapor pressure of molten magnesium.